1. Field of the Invention
The present invention relates to a transformer that can be used as, for example, a leakage transformer.
2. Description of the Related Art
As a leakage transformer, for example, the transformer shown in the following Patent Document 1 is known. For the conventional transformer, in order to reduce iron losses, it is required to increase the number of turns of wire for windings so that a magnetic flux density is decreased. However, when the number of turns of wire increases, the size of the transformer becomes large and that causes a heat generation due to copper losses. Further, in order to realize a large-current in the transformer, it is required to make a wire diameter of wire for windings large. However, as a result of that, a coil winding part gets large and a ferrite core gets large as well. Accordingly, that causes problems such as insulation and an increase of iron losses.
Recently, as for the transformer used for, for example, a vehicle-mounted charger and the like, it is demanded to reduce (downsizing) a height and a plane size of the transformer while realizing a large-current in the transformer so as to correspond to high frequency (30 to 300 kHz). Further, it is also demanded to reduce losses of the transformer due to iron losses and copper losses in the transformer, and further to effectively dissipate the heat generated by the losses in the transformer.
Patent Document 1: Japanese Application Laid Open Publication No. H8-264356